The present invention relates to a freight container and to a method for transporting a load. The invention has particular applicability to a rail freight container.
There are numerous types of rail freight wagons already in existence. A basic type of rail freight wagon uses the wagon itself as the container for a load. In another type, a separate standard container unit is lifted on and off a flat bed rail wagon by special cranes. In a third type, known as a xe2x80x9cpiggy-backxe2x80x9d wagon, a rail wagon accommodates a road vehicle such as a truck or articulated lorry which is driven on and off the rail wagon at special loading points.
Very few freight journeys can be made entirely by rail. There is nearly always a requirement for transport of the freight by road or other means at one or both ends of the rail journey. The freight therefore needs to be switched between transport modes usually at least once in what is known as an xe2x80x9cintermodal freight operationxe2x80x9d.
Existing intermodal rail freight systems require a relatively large investment in terms of both monetary cost and physical space at switching points where freight is transferred from road to rail or from rail to road. This severely restricts the number of available switching points and hence the flexibility that such known systems can provide.
For intermodal road/rail freight transport to be economic with existing wagon types, relatively long distances and large amounts of freight are invariably required between the source and the destination in order for the lower running costs per unit load to counteract the additional costs associated with mode switching. This has been one of the main limiting factors preventing more widespread use of intermodal road/rail freight in preference to road only. It is therefore desirable to increase the available number of switching points which in turn requires that the cost and complexity of the switching points be reduced and to reduce the amount of time required to switch loads between road and rail.
In addition, unless dedicated freight lines are available, it is a fundamental requirement for freight services that they fit in with passenger services timetables. This either means large, slow, infrequent, freight services or smaller, faster, more frequent services. The former is predominant at the present time. There are increasing market pressures for moves towards the latter, due to the xe2x80x9cjust-in-timexe2x80x9d delivery requirements of customers.
It is desirable to run mixed passenger/freight services to make maximum use of available slots on the rail network. With existing systems, issues such as health and safety and speed of loading/unloading limit the freight aspect of mixed traffic to carriage of light parcels.
Rail freight systems that interface with air freight are being examined more closely by the transport industry. Airports such as London Heathrow are being severely limited in their freight growth by the present road aspect of the transport chain. The carriage of palletised freight to the heart of a city by surface or underground train is becoming the preferred solution, although present rail systems cannot easily provide this solution.
According to a first aspect of the present invention, there is provided a freight container for transporting a load from a source to a destination, the container comprising: a plurality of cells each for containing a discrete load; a conveyor for conveying loads between cells; and, a controller for allocating the loads amongst the cells according to the destinations of the individual loads and controlling the conveyor to convey each load to its allocated cell.
At a particular source, loads can be loaded into the container in a fairly random manner with loads being received in unoccupied cells. The loads can then be redistributed between cells within the container so as to group together different loads intended for the same destination. Sorting and redistribution of the loads can take place whilst the container is in transit. When a destination is reached, all of the loads for that destination can be discharged from the container very rapidly. Furthermore, a long series of connected containers, such as in a freight train, can be used with a loading/unloading station or platform which is shorter than the series of connected containers as it is only necessary for the container or containers which include loads for that destination to be parked adjacent the loading/unloading station or platform.
The freight container may include the controller. Alternatively, one or more controllers may be provided separately from the freight container or containers, perhaps at a central fixed location, the controller or controllers communicating with the container or containers, and with each other as necessary, via suitable data communication links such as by radio or via power transmission lines for example. Where a plurality of containers are connected to each other in series, a controller for controlling all of the connected containers may be located in just one of the containers or in a tractor unit for the connected containers for example.
The cells may be arranged in a horizontal plane. Preferably, the cells are arranged in a horizontal array.
In a preferred embodiment, the conveyor comprises means in each cell for unloading a load from the cell.
The conveyor may comprise means for selectively moving a load into and out of a cell in a direction selected from at least two directions for each cell.
In a preferred embodiment, the conveyor comprises means for selectively moving a load into and out of a cell in a direction selected from a direction parallel to the direction of travel of the container and transverse to the direction of travel of the container.
The container preferably comprises means for reading a destination address on a load and providing destination information for each load to the controller. This allows the controller to determine how to redistribute the loads within the container so as to group together the loads as required in a simple manner.
The conveyor may comprise at least one driven roller in each cell for carrying a load and moving said load in a first direction. The conveyor may comprise means in each cell for moving said load in a second direction, the second direction moving means being operable to lift a load from the at least one driven roller to allow said load to be moved in said second direction. The second direction moving means may comprise at least one belt. The first and second directions may for example be parallel to and transverse to the direction of travel of the container.
Each cell may be separated from an adjacent cell by a divider which is movable to allow loads to be conveyed between adjacent cells. A detector may be provided for detecting when a load abuts a divider, the controller being operable on receipt of a signal from the detector indicating that a load abuts a divider to control the conveyor to move said load away from said divider.
The container may have plural access points for loading and unloading of loads.
Alternatively, the container may have a single access point for loading and unloading of loads.
There may be a plurality of containers as described above, each of said containers being connected to at least one other container such that a load can be transferred from one container to another container.
According to a second aspect of the present invention, there is provided a method of transporting plural discrete loads in a container from at least one source to respective destinations, the container having a plurality of cells each for containing a discrete load, the method comprising the steps of: loading said plural discrete loads into the container; identifying which loads are intended for which destinations; allocating the loads amongst the cells according to the destinations of the individual loads; and, conveying each load to its allocated cell.
Preferably, the loads are all initially loaded into cells of the container, and the method comprises the step of redistributing the loads amongst the cells according to the destinations of the individual loads.
The loads may be allocated amongst the cells so that all loads in the container intended for the same destination are conveyed to adjacent or substantially adjacent cells.
The conveying step is preferably carried out whilst the container is in transit between a source and a destination.
According to a third aspect of the present invention, there is provided in combination: a freight container having a plurality of cells each for containing a discrete load and a controller for allocating the loads amongst the cells according to the destinations of the individual loads; and, a loading/unloading station for loading loads into and unloading loads from the container, the loading/unloading station comprising a controller which has a data link to the container controller so that the loading/unloading station controller can determine the location of cells in the container which contain loads to be unloaded from the container by the loading/unloading station and which cells in the container are unoccupied; and, means for unloading loads from cells in the container and for loading loads into cells in the container.